The construction of doorways and doors particularly in dwellings is often carried out simply by installing wooden side plates and a top plate around the door way. Wooden casings are frequently attached to the two edges of the side and top plates. The lock set recesses and hinges are then attached to the plates on opposite sides.
This system does not provide for weather proofing. Weather proofing is usually carried out by attaching some form of weather stripping around the edges of the doorway. All of this requires considerable hand work and the exercise of some degree of skill. It is also time consuming and requires on site labour. An added disadvantage however is that by simply installing the lock and hinge hardware in the wooden plates on opposite sides of the doorway, it is relatively easy for intruders to break in. The wood supporting the lock hardware installed in a typical doorway is relatively easily destroyed by a determined intruder, and the door can then simply be swung open.
For these reasons it is desirable that the doorway sideplates shall be reinforced by metal. In this way when the door lock hardware is installed, it will be much more resistant to destruction by an intruder.
Preferably weatherstripping would also be prefabricated for installation at the same time.
In the past there have been some proposals for the use of extruded plastic in the construction of a door jamb. One such example is shown in U.S. Pat. No. 5,787,660. Another example is shown in U.S. Pat. No. 6,557,309. Plastic extruded material has also been used in framing the door itself so as to provide a door sweep, as shown in U.S. Pat. No. 6,345,431. However, none of these systems have provided a door jamb system in which a combination of wooden door jamb plate and a vinyl extrusion for securing weatherproof trim.